It is generally known that access to the well casing annulus defined between the tubing string and outer casing of a well, without removing the installed equipment which is used for production may be desirable on occasion. This access would greatly reduce the cost of servicing a well when the well bore has plugged off as a result of sand, wax or other accumulations and build ups in the well bore as the production string need not be removed. Such access also permits measuring devices to be injected into the casing annulus without the need for the same costly equipment to open the wellhead.
U.S. Pat. No. 6,315,046 and the corresponding Canadian patent 2,268,223 both to Jack et al each disclose a method of servicing a well in which a casing spool is provided for connection to the outer casing of the well which incorporates access passages into the central flow area. In order to make use of the access ports a costly installation is required in which costly wellhead equipment is made to be redundant with the installation of the new components disclosed by Jack et al. In addition by providing access passages formed integrally with a casing spool, the configuration of the casing spool access ports is such that damage may be incurred as the endless tubing is fed into the feed passages.
Other patents related to servicing of a well include U.S. Pat. No. 6,142,232 to Troutt et al, U.S. Pat. No. 6,484,807 to Allen and U.S. Pat. No. 5,865,249 to Gipson et al and Canadian patent application number 2,228,203 also to Gipson et al. In each instance the wellhead must be specially configured and/or removed to permit servicing access to the well. Such reconfiguration of the wellhead is costly as special equipment must be used to remove the existing production equipment and a endless tubing unit must also be used.